This invention relates to a colored contact lens that can enhance or modify the color of the wearer's eye, while providing a very natural appearance.
Early attempts to provide a contact lens that can enhance or modify the color of the wearer's eye suffered various shortcomings. Lenses that provided a transparent tint over the iris were not able to change dark eye colors to light colors, and provided a bland appearance. Lenses that provided a continuous opaque pattern over the iris looked unnatural. Lenses that provided an opaque pattern based on photographic or artistic reproduction of the iris were expensive to make. Such lenses also reduced the amount of oxygen that is transmitted through the lens.
Commercial success was achieved by the colored contact lens described in U.S. Pat. No. 4,582,402 to Knapp. The Knapp color contact lens was achieved by printing an intermittent pattern of opaque ink dots over the area of the contact lens that covers the iris. Although the intermittent pattern of dots does not fully cover the iris, it provides a sufficient density of dots such that a masking effect that gives the appearance of a continuous color is observed by the ordinary viewer. Thus, the intermittent dot pattern is able to provide a sufficient appearance of continuity to effectively and substantially modify the wearer's eye color, such as from brown to blue. At the same time, the intermittent pattern allows oxygen to pass through the interstices between the dots. Such contact lenses now comprise a significant share of the contact lens market.
Various efforts have been made to improve upon the success of the Knapp lens. U.S. Pat. No. 5,414,477 to Jahnke discloses the application of the intermittent ink pattern in two portions of two distinct shades of colorant to provide a more natural appearance. However, adding two shades of colorant requires two applications of colorants. This adds to the cost of producing a lens, and increases the number of lenses rejected during the lens manufacturing process.
Jahnke also claims a pattern that comprises three concentric portions, wherein the first and third portions have opaque coloring, while the second portion is non-opaque. However, this lens has not achieved consumer acceptance.
U.S. Pat. No. 5,120,121 to Rawlings et al. discloses a cluster of interconnecting lines radiating from the periphery of the pupil portion to the periphery of the iris portion. FIG. 2 in Ciba-Geigy European Patent Publication No. 0 472 496 A2 shows a contact lens having a pattern of lines that attempts to mimic the lines found in the iris.
Despite these efforts, the contact lens industry continues to seek a low-cost, colored lens that can enhance or modify the eye color, while providing the depth and texture that is inherent in the iris.